The invention relates to a drive arrangement of an auxiliary device, especially a water pump, on a housing wall of an internal combustion engine.
In a drive installation known from U.S. Pat. No. 3,728,995 for the oil pump of an internal combustion engine, a drive gear is keyed onto a drive shaft and, on the other side, a gear wheel of a geared oil pump is likewise mounted by means of a fitting key. In order to ensure exactly true rotation, very tight manufacturing tolerances must be maintained in this construction. If the oil pump is to be dismounted for repair purposes, screws must be released on both sides of the drive shaft, which is very difficult in many installation types, and both gear wheels must be pulled off their wedged-on connections.
An object of the invention resides in constructing a drive arrangement and bearing installation of an auxiliary device, for example a water pump, in such a way that less stringent manufacturing tolerances are permissible and a simple dismounting of the pump is made possible without requiring simultaneous disassembly of the drive wheel. This latter requirement is posed, above all, if the water pump is suspended on the drive train of crankshaft-camshaft, for in this case, due to the disassembly of the drive wheel, the relative position of the camshaft with respect to the crankshaft would be altered and would have to be readjusted.
In accordance with the present invention, in an internal combustion engine having a housing wall, an auxiliary device mounted on the housing wall, and a drive wheel positioned on a first side of the housing wall, a drive arrangement for driving the auxiliary device is provided. The drive arrangement comprises a driven wheel positioned on a second side of the housing wall and a drive shaft supported by the housing wall. The driving wheel and driven wheel are mounted and centered on the drive shaft. A lug means is positioned on the first side of the housing wall for drivingly connecting the drive wheel to the drive shaft. A threaded connector means is positioned on the second side of the housing wall for securing the drive shaft to the driven wheel.
Preferably a stop at the drive shaft and a threaded connection are employed to tighten the drive wheel from one side, the pump wheel, with interposition of a sleeve centered on the drive shaft, from the other side against the inner race of a ball bearing. The outer race of the ball bearing is fixed either directly in a housing wall of an internal combustion engine or in the one housing half of the water pump flanged to the housing wall.
Such a drive arrangement and bearing installation makes it possible to utilize a pin transversely penetrating the drive shaft as the stop at the drive shaft. The pin is extensible through two longitudinal grooves of the drive wheel and, after twisting in the range of annular-segment recesses at the end face, is fixable in the circumferential direction as well as axially on the end face of the drive wheel. Accordingly, for mounting the pump wheel, the entire drive connection of crankshaft-camshaft can remain unchanged. The assembly can be effected quickly and reliable. The present invention obviates the need for the use of tight-tolerance, expensive fittings during the manufacture of the connecting parts.
Further objects, features, and advantages of the present invention will become more apparent from the following description when taken with the accompanying drawings which show, for purposes of illustration only, embodiments in accordance with the present invention.